What type of leak could be identified through thermography in air leakage testing?

Thermography is a powerful tool used in air leakage testing, particularly for identifying hidden air leaks within the building envelope. This method utilizes infrared cameras to visualize temperature differences on surfaces, which can reveal areas where air is infiltrating or exfiltrating.

When air leaks occur, they can cause temperature variations due to the transfer of heated or cooled air between the interior and exterior of a building. These temperature discrepancies are often not visible to the naked eye, making thermography an invaluable technique for locating leaks that are concealed behind walls, ceilings, or other structural components.

Surface cracks in walls, obvious openings like doors and windows, and condensation in insulation materials can typically be detected through more conventional means, such as visual inspection or moisture meters. However, these options do not reflect the unique capacity of thermography to uncover hidden issues. Hence, identifying hidden air leaks is why that choice stands out as the correct answer in the context of air leakage testing.